ApplyRules[%,SigmaLimitSixRule]

Out[16]=

  -R          R          R          R          R
    acbd;ef    acbe;df    acbf;de    adbc;ef    adbe;cf
  --------- - -------- - -------- - -------- - -------- - 
      5          5          5          5          5
   
    R          R          R          R          R
     adbf;ce    aebc;df    aebd;cf    aebf;cd    afbc;de
    -------- - -------- - -------- - -------- - -------- - 
       5          5          5          5          5
   
                                    p             p
    R          R          R     R       R     R
     afbd;ce    afbe;cd    pedf  acb     pfde  acb
    -------- - -------- + ----------- + ----------- + 
       5          5           45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pecf  adb     pfce  adb     pebf  adc     pfbe  adc
    ----------- + ----------- + ----------- + ----------- + 
        45            45            45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pdcf  aeb     pfcd  aeb     pdbf  aec     pfbd  aec
    ----------- + ----------- + ----------- + ----------- + 
        45            45            45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pcbf  aed     pfbc  aed     pdce  afb     pecd  afb
    ----------- + ----------- + ----------- + ----------- + 
        45            45            45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pdbe  afc     pebd  afc     pcbe  afd     pebc  afd
    ----------- + ----------- + ----------- + ----------- + 
        45            45            45            45
   
              p             p           p             p
    R     R       R     R       R     R       R     R
     pcbd  afe     pdbc  afe     pedf  a bc    pfde  a bc
    ----------- + ----------- + ----------- + ----------- + 
        45            45            18            18
   
            p             p             p             p
    R     R       R     R       R     R       R     R
     pecf  a bd    pfce  a bd    pdcf  a be    pfcd  a be
    ----------- + ----------- + ----------- + ----------- + 
        18            18            18            18
   
            p             p             p             p
    R     R       R     R       R     R       R     R
     pdce  a bf    pecd  a bf    pebf  a cd    pfbe  a cd
    ----------- + ----------- + ----------- + ----------- + 
        18            18            18            18
   
            p             p             p             p
    R     R       R     R       R     R       R     R
     pdbf  a ce    pfbd  a ce    pdbe  a cf    pebd  a cf
    ----------- + ----------- + ----------- + ----------- + 
        18            18            18            18
   
            p             p             p             p
    R     R       R     R       R     R       R     R
     pcbf  a de    pfbc  a de    pcbe  a df    pebc  a df
    ----------- + ----------- + ----------- + ----------- + 
        18            18            18            18
   
            p             p               p             p
    R     R       R     R       R     R       R     R
     pcbd  a ef    pdbc  a ef    peaf  bdc     pfae  bdc
    ----------- + ----------- + ----------- + ----------- + 
        18            18            45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pdaf  bec     pfad  bec     pcaf  bed     pfac  bed
    ----------- + ----------- + ----------- + ----------- + 
        45            45            45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pdae  bfc     pead  bfc     pcae  bfd     peac  bfd
    ----------- + ----------- + ----------- + ----------- + 
        45            45            45            45
   
              p             p           p             p
    R     R       R     R       R     R       R     R
     pcad  bfe     pdac  bfe     peaf  b cd    pfae  b cd
    ----------- + ----------- + ----------- + ----------- + 
        45            45            18            18
   
            p             p             p             p
    R     R       R     R       R     R       R     R
     pdaf  b ce    pfad  b ce    pdae  b cf    pead  b cf
    ----------- + ----------- + ----------- + ----------- + 
        18            18            18            18
   
            p             p             p             p
    R     R       R     R       R     R       R     R
     pcaf  b de    pfac  b de    pcae  b df    peac  b df
    ----------- + ----------- + ----------- + ----------- + 
        18            18            18            18
   
            p             p               p             p
    R     R       R     R       R     R       R     R
     pcad  b ef    pdac  b ef    pbaf  ced     pfab  ced
    ----------- + ----------- + ----------- + ----------- + 
        18            18            45            45
   
              p             p             p             p
    R     R       R     R       R     R       R     R
     pbae  cfd     peab  cfd     pbad  cfe     pdab  cfe
    ----------- + ----------- + ----------- + ----------- - 
        45            45            45            45
   
               p             p                p
    13 R     R       R     R       13 R     R
        pbaf  c de    pfab  c de       pbae  c df
    -------------- + ----------- - -------------- + 
          90             18              90
   
            p                p             p
    R     R       13 R     R       R     R
     peab  c df       pbad  c ef    pdab  c ef
    ----------- - -------------- + ----------- + 
        18              90             18
   
              p             p              p             p
    R     R       R     R       13 R     R       R     R
     pbac  dfe     pcab  dfe        pbac  d ef    pcab  d ef
    ----------- + ----------- - -------------- + -----------
        45            45              90             18

Up to A Very Large Scale Pattern Matching Problem in MathTensor